Setup bullet gem and get rid of all N+1 Queries

[rbclark]

The recent refactor to merge the ECTF + CTF scoreboards together has unfortunately added a huge number of N+1 queries to our codebase. We need to go through and clean these up as much as we can and also add the bullet gem: https://semaphoreci.com/blog/2017/08/09/faster-rails-eliminating-n-plus-one-queries.html to try to make sure they don't show back up in the future.